Explanation

High quality steel with high requirements for the control of sulfur, scale and other impurities and trace residual elements. The sulfur and phosphorus content of high-quality non alloy structural steel in China shall not exceed 0.040% and 0.035% respectively; The sulfur and phosphorus content of high-quality non alloy tool steel shall not be greater than 0.030% and 0.035% respectively; At the same time, the fluctuation range of carbon content and the content of residual elements such as nickel, chromium, copper and non-metallic inclusions are also more stringent than those of ordinary quality steel.

Classification